Sepsis is a life-threatening complication of infection that results in over 250,000 deaths per year in the United States. There is a strong correlation between reduced levels of lymphocytes, such as CD8+ and CD4+ T cells, and increased mortality; therefore, strategies aimed to increase these cells have therapeutic potential. The cytokine IL-7 prevents lymphocyte death, increases lymphocyte proliferation, and has been shown to improve intestinal lymphocyte counts in patients with HIV-1. In this episode, Richard Hotchkiss details the results from a prospective, randomized, double-blind, placebo-controlled trial of recombinant human IL-7 in patients with septic shock and severe lymphocytopenia. IL-7 reversed the loss of lymphocytes in septic patients, suggesting that this approach be further explored.
BACKGROUND. A defining pathophysiologic feature of sepsis is profound apoptosis-induced death and depletion of CD4+ and CD8+ T cells. Interleukin-7 (IL-7) is an antiapoptotic common γ-chain cytokine that is essential for lymphocyte proliferation and survival. Clinical trials of IL-7 in over 390 oncologic and lymphopenic patients showed that IL-7 was safe, invariably increased CD4+ and CD8+ lymphocyte counts, and improved immunity. METHODS. We conducted a prospective, randomized, double-blind, placebo-controlled trial of recombinant human IL-7 (CYT107) in patients with septic shock and severe lymphopenia. Twenty-seven patients at academic sites in France and the United States received CYT107 or placebo for 4 weeks. Primary aims were to determine the safety of CYT107 in sepsis and its ability to reverse lymphopenia. RESULTS. CYT107 was well tolerated without evidence of inducing cytokine storm or worsening inflammation or organ dysfunction. CYT107 caused a 3- to 4-fold increase in absolute lymphocyte counts and in circulating CD4+ and CD8+ T cells that persisted for weeks after drug administration. CYT107 also increased T cell proliferation and activation. CONCLUSIONS. This is the first trial of an immunoadjuvant therapy targeting defects in adaptive immunity in patients with sepsis. CYT107 reversed the marked loss of CD4+ and CD8+ immune effector cells, a hallmark of sepsis and a likely key mechanism in its morbidity and mortality. CYT107 represents a potential new way forward in the treatment of patients with sepsis by restoring adaptive immunity. Such immune-based therapy should be broadly protective against diverse pathogens including multidrug resistant bacteria that preferentially target patients with impaired immunity. TRIAL REGISTRATION. Trials registered at clinicaltrials.gov: NCT02640807 and NCT02797431. FUNDING. Revimmune, NIH National Institute of General Medical Sciences GM44118.
Bruno Francois, Robin Jeannet, Thomas Daix, Andrew H. Walton, Matthew S. Shotwell, Jacqueline Unsinger, Guillaume Monneret, Thomas Rimmelé, Teresa Blood, Michel Morre, Anne Gregoire, Gail A. Mayo, Jane Blood, Scott K. Durum, Edward R. Sherwood, Richard S. Hotchkiss